In shaped plastic elements, in particular in expandable soft trims for motor vehicles such as for dashboards or for use as interior coverings, it is often desirable to provide a decorative seam, or a plurality of decorative seams, on the various plastic elements for the sake of appearance. This goal can be attained by using what is known as the powder slush method.
This known method uses powder (pulverized plastic) and electroforming molds for the plastic element that is to be produced and provided with a decorative seam. The powder is distributed on the mold wall by pivoting motions of the electroforming mold, and by means of an ensuing solidification of the powder, the plastic element--such as a dashboard--corresponding to the electroforming mold can be produced; in principle, it is also possible to produce decorative seams using this method.
However, the known powder slush method has serious disadvantages. Since not all plastics can be pulverized, the known method is restricted in terms of the field of its application. In practical usage, certain peripheral conditions such as pourability, granular consistency of the powder, and so forth must also be taken into consideration, because these parameters are highly important in the production of plastic elements. In practice, this condition further limits the field of application.
Furthermore, high tool costs and machine cost prices in the known method result in considerable expenses that are passed on to the sale price of the finished plastic element. Finally, the production of a shaped plastic element using the powder slush method is quite time-consuming, which is also unfavorable from an economic standpoint.